They are some of the greatest treasures of Tibetan Buddhist culture: ancient murals showing the life of the Buddha and the secrets of meditation. Many are hidden in remote monasteries or temples whose walls are crumbling, but a remarkable project has recorded the paintings before they disappear for ever.
The American photographer and writer Thomas Laird spent a decade living among yak herders, farmers and monks while travelling across the Tibetan plateau in search of masterpieces that few have been able to see, let alone photograph.